rtl_tcp SDR1.5.6 - App Store

An RTL-SDR Software Defined Radio receiver app for iOS devices. Listen to AM, FM, SSB and CW radio signals. View an RF spectrum and waterfall. Connect, via the rtl_tcp network protocol, to networked RTL-SDR USB peripherals.

This app requires an external rtl_tcp server. iOS devices do not currently support the direct connection of USB peripherals such as an RTL-SDR. Thus, the use of this app requires network access to a server, such as a Raspberry Pi (or Mac), with an RTL-SDR unit plugged into its USB port, and running the rtl_tcp protocol at an TCP/IP network address accessible from your iOS device. This allows a Raspberry Pi (or Mac) to act, essentially, as the USB port adapter for your iOS device. The rtl_tcp SDR app can also connect to hfp_tcp for the Airspy HF+, rsp_tcp for SDRPlay devices, and lmm_tcp for the LimeSDR Mini; see GitHub for server source code. This app can also connect to a Hermes Lite 2 QRP transceiver directly, if it has a known IP address, or through an hl2_tcp server.

No support is provided for installing any of the rtl_tcp or other tcp software needed to use this app (with a Raspberry Pi, or otherwise). Please do not download this app unless you are already familiar with Software Defined Radio, have an RTL-SDR or equivalent USB SDR peripheral, and have already installed and tested rtl_tcp on your Raspberry Pi, Mac, or other server. Note that this app requires a very high bandwidth network connection in order to receive streams of real-time RF samples from an RTL-SDR. It is recommended that your rtl_tcp server be on a wired connection rather than on the same WiFi as your iOS device.

Version History Stability enhancements and minor bug fixes for SSB modulation and CW decoding. 1.5.6 Jan 21 Bug fixes for HL2 PTT/keying. 1.5.5 04/24/2025 Bug fixes and stability enhancements.
Improved support for Hermes Lite 2 CW & SSB transmit.
Added support for the CTR2 MIDI control knob. 1.5.4 03/21/2025 Bug fixes and stability enhancements 1.5.3 12/29/2024 Stability enhancements and Bug fixes (FM audio spectrum, SSB, noise reduction, and audio limiter) 1.5.2 05/15/2024 Improved Noise Reduction algorithm.
Multiple bug fixes plus some performance and stability enhancements. 1.5.1 01/20/2024 Bug fixes and performance enhancements 1.4.8 05/11/2023 Bug fix for compatibility with the latest hl2_tcp server for Hermes Lite 2 SDRs, plus other bug fixes and stability enhancements. 1.4.7 01/06/2023 Bug fixes and stability improvements
Improved S-meter calibration 1.4.6 10/28/2022 - Added 2.5 Msps RTL-SDR sample rate support
- Improved Voiceover support
- Improved Hermes Lite 2 CW and SSB modulation
- Changed generated Share setting URLs
- Added an audio route picker option
- Fixed an S-meter positioning bug
- Other bug fixes and reliability and OS compatibility improvements 1.4.5 02/24/2022 This release contains a few minor bug fixes 1.4.3 11/07/2021 Bug fixes and performance enhancements. 1.4.2 07/11/2021 - Added a VFO A/B switch
- New larger S-Meter on iPads
- Improved frequency markings on the spectrum display
- Minor improvements to the audio filtering
- Several small bug fixes 1.4.1 05/30/2021 Minor bug fixes for tuning while zoomed in. 1.3.9 02/14/2021 Bug fixes and improved support for new OS releases.
Bug fixes for audio filters and spectrum display.
Added support for the Hermes Lite 2 SDR. 1.3.7 10/05/2020 Bug fix for squelch function. Previous version included bug fixes for audio filtering. 1.3.6 06/15/2020 Bug fixes and performance enhancements. 1.3.5 06/14/2020 A few minor bug fixes and performance enhancements 1.3.4 04/04/2020 - Bug fixes and improvements to audio and CW filters
- Added support for lower Airspy HF+ and HF+ Discovery sample rates 1.3.2 12/21/2019 Bug fix for a problem tuning via swipe gestures 1.2.7 10/01/2019 Minor bug fixes and improved support for iOS 13 1.2.6 09/24/2019 - Bug fix for a problem setting higher RTL-SDR sample rates
- Updated support for HF+ Discovery sample rates 1.2.5 08/23/2019 - Bug fixes
- UI fixes for iPhone SE sized displays
- Updated support for hfp_tcp & new HF+ sample rates
- Added an unZoom button 1.2.4 08/09/2019 - Bug fix for CW filter enable/disable.
- Improvements to both SSB and CW filters. 1.2.3 07/30/2019 Improvements to spectrum zoom.
Bug fixes for frequency and audio level settings.
Reliability enhancements. 1.2.2 05/16/2019